supplementary materials

In the structure of the title coordination polymer, {(C8H20N)[Sn3(CH3)9(SO4)2]}n, each of the three SnIV atoms is coordinated in a trigonal-bipyramidal manner by three methyl groups in the equatorial plane and by two O atoms of SO42- anions in the axial positions. The 3-bridging mode of the sulfate anions leads to the formation of corrugated anionic layers parallel to (100). The uncoordinating O atom of one of the two SO42- anions is N-HO hydrogen-bonded to the dibutylammonium cation interconnecting the anionic sheets. The structure is partially disordered. The dibutyl ammonium ion is found on two positions with an occupancy ratio of 0.525 (10):0.475 (10), and one sulfate group with three connecting trimethyl stannyl groups is also positionally disordered over two sets of sites with an occupancy ratio of 0.725 (4):0.275 (4).

Various applications of organotin(IV) compounds explain the focus of research
teams, including ours, to the search and characterisation of new organotin(IV)
compounds, e.g. Evans & Karpel (1985); Basu et al.
(2005); Kapoor
et al. (2005); Samuel et al. (2002). In the scope
of our research
on the
coordination ability of oxyanions (Molloy et al., 1989; Diop
et al., 2002) and our interest to synthesize new organotin(IV)
derivatives for biological tests, we elucidate here the structure of the title
compound, (C8H20N)[(Sn(CH3)3)3(SO4)2], (I).

Compound (I) has a polymeric structure consisting of three O2SnC3 moieties,
and two different tridentate sulfate ligands (Fig. 1). In the
two-dimensional polymeric structure that extends parallel to (100) (Fig. 2)
all tin(IV) atoms are five-coordinate, with the trigonal (CH3)3Sn units
axially bridged through sulfate groups.
The angles between the apical positions within the trigonal-bipyramidal
arrangement indicate a slight deviation from linearity for Sn1
and Sn2 (O1—Sn1—O7 = 172.44 (8)°; O8—Sn2—O2 = 176.59 (11)°)
and a considerable deviation for Sn3 (O4—Sn3—O5 = 168.64 (10)°). The
Sn—O bonds are in the excepted range [2.262 (2)–2.305 (2) Å] and are
shorter than the Sn—O distances in (Bu4N)HSO4.Sn(CH3)3Cl [2.450 (5)]
(Diallo et al., 2009). The dibutylammonium cation connects
adjacent
anionic layers through N—H···O hydrogen bonding into a three-dimensional
network structure (Fig. 3).

(Bu2NH2)2SO4.H2O (L) was obtained on mixing a water solution
of NH2SO3H (0.15 g, 1.5 mmol) with Bu2NH2 (0.78 g, 3 mmol). Hydrolysis
of NH2SO3H in basic media has yielded the sulfate. The title compound has
been obtained by reacting (L) (0.15 g, 0.4 mmol) with trimethyltin
chloride (0.16 g, 0.8 mmol) in ethanol. Slow solvent evaporation yielded
colourless crystals. SnMe3Cl, the acid NH2SO3H and Bu2NH2 were
purchased from Aldrich and used without further purification.

Three reflections, (0 1 1), (1 0 0) and (1 1 1), were obstructed by the beam
stop and were omitted from the refinement. Disorder is observed for one of the
sulfate groups and for the dibutyl ammonium ion. The disorder of the sulfate
group extends to the neighboring trimethyl stannyl groups and the occupancy
ratio refined to 0.725 (4):0.275 (4). The occupancy ratio for the dibutyl
ammonium ion is 0.525 (10):0.475 (10). All equivalent disordered moieties
were restrained to have similar geometries (SAME command in SHELXTL).
Equivalent methyl groups of trimethyl stannyl groups were restrained to
have similar ADPs, as were Sn1 and Sn1B and Sn2 and Sn2B. The disordered atoms
N1, N1B, C13, C13B, C14 and C14B of the dibutyl ammonium ion were restrained
to be approximately isotropic (ISOR 0.005 command in SHELXTL).
Methyl H atoms were placed onto calculated positions and refined using a
riding model, with C—H distances of 0.98 Å and Uiso(H)=
1.5Ueq(C); methylene H atoms were refined with C—H distances of
0.99 Å and Uiso(H)= 1.2Ueq(C); ammonium H atoms were
refined with N—H distances of 0.90 Å and Uiso(H)=
1.2Ueq(N).

Fig. 1. The asymmetric unit of the structure of compound (I) with displacement
ellipsoids drawn at the 50° probability level. The minor components
of the disordered parts within the structure are not shown.

Fig. 2. The two-dimensional [(SnMe3)3(SO4)2]- anionic sheet structure of
(I). Hydrogen atoms and the Bu2NH2+ cations have been omitted for
clarity. The minor components of the disordered parts
within the structure are not shown.

Fig. 3. The linking of the sheets through N—H···O hydrogen bonds between
the Bu2NH2+ cations and the stannate(IV) sheets (red dotted lines).
Only H atoms involved in hydrogen bond interactions are shown for
the sake of clarity.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger.